English verb conjugation
MUST WATER-SKI

Regular verb: water-ski - water-skied - water-skied

Affirmation

Simple form	V-ing form
I must water-ski you must water-ski he must water-ski we must water-ski you must water-ski they must water-ski	I must be water-skiing you must be water-skiing he must be water-skiing we must be water-skiing you must be water-skiing they must be water-skiing
Perfect	V-ing perfect
I must have water-skied you must have water-skied he must have water-skied we must have water-skied you must have water-skied they must have water-skied	I must have been water-skiing you must have been water-skiing he must have been water-skiing we must have been water-skiing you must have been water-skiing they must have been water-skiing

Negation

Simple form	V-ing form
I mustn't water-ski you mustn't water-ski he mustn't water-ski we mustn't water-ski you mustn't water-ski they mustn't water-ski	I mustn't be water-skiing you mustn't be water-skiing he mustn't be water-skiing we mustn't be water-skiing you mustn't be water-skiing they mustn't be water-skiing
Perfect	V-ing perfect
I mustn't have water-skied you mustn't have water-skied he mustn't have water-skied we mustn't have water-skied you mustn't have water-skied they mustn't have water-skied	I mustn't have been water-skiing you mustn't have been water-skiing he mustn't have been water-skiing we mustn't have been water-skiing you mustn't have been water-skiing they mustn't have been water-skiing

Interrogative form

Simple form	V-ing form
must I water-ski? must you water-ski? must he water-ski? must we water-ski? must you water-ski? must they water-ski?	must I be water-skiing? must you be water-skiing? must he be water-skiing? must we be water-skiing? must you be water-skiing? must they be water-skiing?
Perfect	V-ing perfect
must I have water-skied? must you have water-skied? must he have water-skied? must we have water-skied? must you have water-skied? must they have water-skied?	must I have been water-skiing? must you have been water-skiing? must he have been water-skiing? must we have been water-skiing? must you have been water-skiing? must they have been water-skiing?

Interro-negative form

Simple form	V-ing form
mustn't I water-ski? mustn't you water-ski? mustn't he water-ski? mustn't we water-ski? mustn't you water-ski? mustn't they water-ski?	mustn't I be water-skiing? mustn't you be water-skiing? mustn't he be water-skiing? mustn't we be water-skiing? mustn't you be water-skiing? mustn't they be water-skiing?
Perfect	V-ing perfect
mustn't I have water-skied? mustn't you have water-skied? mustn't he have water-skied? mustn't we have water-skied? mustn't you have water-skied? mustn't they have water-skied?	mustn't I have been water-skiing? mustn't you have been water-skiing? mustn't he have been water-skiing? mustn't we have been water-skiing? mustn't you have been water-skiing? mustn't they have been water-skiing?